I agree that switching to a tool should not change the structure of the doc. May be what we need is a better way to apply masks or clippath.
IMO having a new option bar for Selector tool should be cool. The option bar should give different options if one object is select or if several are. In the last case, we could have button to add clip or mask, but align options
In the first case, we could also add automagically selection presets that could act as some kind of shortcuts to the find dialog : i.e. select all objects by a fill or stroke color same as selected object, ect
pygmee
This looks like a good idea on the face of it but it introduces a new concept - an "intrinsic image mask". Why only images have such mask by default? Before long you will have users asking why it doesn't work on groups as well as images. Users should learn what is a clipping path instead, because this concept is sufficient. This could be done by improving the visibility of clipping-related options, and enhancing the clipping workflow in general.